Water-repellent coating composition



Patented June 27, 1933 UNITED STATES PATENT OFFICE GEORGE E. ENSMINGER,OF NEW BRUNSWICK, NEW JERSEY, ASSIGNOR TO E. I. DU PONT DE NEMOUBS &:COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWAREWATER-REPELLENT COATING COMPOSITION No Drawing.

This invention relates to water-repellent coatin compositions and moreparticularly to sue coating compositions designed for use on fabrics.paper, and similar fibrous bases.

Heretofore many water-repellent coating compositions for use on fabrics,and the like, have been known, but fabrics coated or impregnated withsuch compositions have always had some material drawback. Although someof these compositions had several desirable roperties, a composition hasnot heretofore en known that, when applied to a fabric, would give afabric having a high degree of water-repellency without altering theappearance of the fabric or its inherent pliabihty, softness, andsuppleness, in other words, a fabric substantially unchanged in anymanner except that it was highly waterrepellent. Many of thesecompositions of the prior art had an objectionable inherent odor ordeveloped such an odor on ageing, or had a tendency to discolor.

An object of the present invention is to provide a coatin compositionwhich, when applied to a fabric, or the like, will give the fa ricexcellent water-repellent properties without otherwise altering thefabric. A further object is to provide such a composition which issubstantially odorless and has no tendency to develop an objectionableodor on ageing, or to become discolored. A particular object of thisinvention is to provide such a composition that will not decrease thesuppleness or pliability of the fabric, as the compositions heretoforeknown have generally done.

The above objects are accomplished according to the present invention bythe utilization of a composition comprising a cellulose derivative,preferably cellulose nitrate, a water-repellent wax, and a non-volatileoil, with or without the addition of a plasticizer for the cellulosederivative, dissolved in a suitable solvent mixture.

Throughout the specification and claims, the viscosity of the cellulosenitrate is ex-, pressed in seconds determined according to A. S. TeM.Tentative Specifications Desig- Application filed November 6, 1931.Serial No. 573,515.

nation D30131T, Formula A (12.2% solution).

The following examples are 'ven to illustrate two formulas coming wit inthe scope of the present invention:

Example 1.U86 of high meltz'n pamfiin was and plasticizer for the calulose m3- tmte Example 2.-U8e of J apan was: and no plastz'cz'eer forthe cellulose nitrate Per cent Nitrocotton (15-20 seconds) 1.0 Japan wax3. 0 Petrolatum (naphthene base oil)--.. 3. 0 Toluol 30.0 Ethyl acetate33.0 Butyl acetate 30.0

The compositions of the above examples are repared by a simple mixingoperation. Pre erably the wax is added to the toluol in a mixer andagitated until dissolved, and the cellulose nitrate is separatelydissolved in the ester solvents and alcohol,the other materials thenbeing added to the nitrocellulose solution, which is then combined withthe wax solution. a J

The above examples are given merely,v to illustrate specific embodimentsof the invention and it will be understood that the ingredients andproportions of the above compositions may be widely varied withoutdeparting from the scope of the present invention.

In these coating compositions the cellu lose derivative, preferablycellulose nitrate,

cosity above four seconds and the best results have been obtained with acellulose nitrate having a viscosity of 15-20 seconds in treatingrelatively fine fabrics, such as silks, et cetera. Where the fabric tobe treated is relatively heavy, such as canvas, and duck, a higherviscosity cellulose nitrate, havin a viscosity of the order of 1000seconds, as

been found more suitable. Various kinds of cellulose nitrate, such ascolloidal nitrocotton, film scrap, smokeless gun powder, and celluloid,may be used in place of the ordinary nitrated cotton disclosed in theabove examples.

The wax in these compositions gives increased water-repellency tofabrics treated with the compositions. Obviously a wide variety of waxesmay be used, but the brittle, non-tack hi h melting paraffin waxes arepreferre apan wax and also hydrogenated sperm oil are articularly wellsuited or this purpose. ther waxes, such as ceresin, candelilla, Chineseinsect, bayberry, montan, glyceril stearate, and glycol stearate, may beused.

The non-volatile oil in these compositions is important in obtaining acomposition that will not stiffen fabric. Apparently the oil functionsas a'softener for the wax. A nonvolatile naphthene base oil, such asPetrolatum, gives excellent results, although many other oils, such asneats-foot, olive cottonseed, castor, blown cottonseed, boiled linseed,paraflin, Nujol, and heav petroleum oils, are suitable. Oleic acid anlanolin have also been used with succem.

As will be apparent to those skilled in the art, the solvent mixtureused in these compositions can be varied widely and the examples merelyillustrate typical solvent mixtures. The usual cellulose derivativesolvents and diluents and the usual wax solvents may well impartingpliability and softness to fabrics treated wit the compositions.

The roportion of non-volatiles in these compositions should not exceed20% by weight, and it is rather impractical to use less than 1% .byweight of non-volatiles. By the term non-volatiles as used herein ismeant the cellulose derivative, the wax, the non-volatile oil and theplasticizer for the cellulose derivative. It will be understood that itis not intended to exclude oils which are substantially non-volatile butdo volatilize to a certain extent. The proportion of wax, plusnon-volatile oil, to cellulose derivative preferably should be keptbetween 2-15 parts by weight to one part by weight of the cellulosederivative, and the proportion of non-volatile oil to wax preferablyabout 1 to 1, or an excess of oil. In treating various fabrics andemploying different specific ingredients some variations in theproportions given above may be found more suitable for certain purposes,but the preferred proportions are as above indicated.

The compositions of the present invention may be applied to fabrics by anumber of known methods but it is preferred to apply these compositionssimply by immersing the fabric, or paper, or material to be treateduntil it is thoroughly saturated and then wringing out the excesscoating material by squeeze rolls or centrifuging. This process isconducted at room temperature generally, although in using thecomposition specifically disclosed in Example 1, it is preferred tocarry out the process at a temperature not lower than 73 F., since thereis some tendency for the high melting parafiin wax to precipitate out ifthe operating temperature is below 73 F. In the case of the compositionspecifically disclosed in Example 2, it is not necessary to observe thistem erature requirement since the Japan wax oes not show any tendency toprecipitate out. After the excess coating material has been removed thevolatile solvents of the composition are then removed by drying thefabric, or paper, at ordinary or slightly elevated temperatures.

Fabrics treated with the coating compositions of the present inventionare highly water-repellent and substantially unaltered in up earance orfeel. In fact, in many cases the p iability and softness of the fabricappears to be actually increased by treatment with these compositions.Fabric so treated is substantially odorless and does not have anytendency to become discolored on ageing. The coating composition beingsubstantially chemically inert with respect to the fabric, has nodeleterious effect thereon. lieved that the su riority of the presentcompositions over t ose heretofore used lies,

to some extent at least, in the fact that the coating compositionsurrounds each fiber of It is bethe fabric without bridging over theinterstices of the fabric, this bridging over a parently bein one of themain causes of t e increased sti ness of fabric treated by processesheretofore known.

Usually in the heretofore known processes for waterproofing fabric, acomposition has been applied to the fabric by means of a doctor knifewhich has a tendency to cause this bridging over of the interstices inthe fabric.

The low non-volatile content of the present compositions permits easypenetration of the fibers of the fabric well beneath the surface, thusaffording uniform and complete coating of each individual fiber, whichresults in a high degree of water-repellency without increasing thestifi'ness or altering the feel of the fabric.

These compositions find particular use where it is desired to treat allvarieties of fabrics to give them the property of waterrepellency.without altering their inherent apearance and feel. Silks, woolens,cotton abrics, velvets, rayon, paper, and the like, may be successfullytreated with these compositions, as well as the heavier fabrics, such astarpaulin, canvas, duck, and teal.

As many apparently widely diflerent embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as defined in the appended claims.

I claim:

1. A water-repellent coatin composition for fabrics and the likecomprising a cellulose derivative, a water-repellent wax, and anonvolatile oil, the amount of wax and oil together being at least equalto twice the amount of cellulose derivative employed and the amount ofoil being at least equal to the amount of wax employed, the non-volatileingredients amounting to 1-20% by weight of the composition.

2. A water-repellent coating composition for fabrics and the likecomprlsing cellulose nitrate, a water-repellent wax, and a nonvolatileoil, the amount of wax and oil together being at least equal to twicethe amount of cellulose nitrate employed and the amount of oil being atleast equal to the amount of wax employed, the non-volatile ingredientsamounting to 120% by weight of the composition.

3. A water-repellent coating composition for fabrics and the likecomprising cellulose nitrate, a high melting paraflin wax, a nonvolatileoil, and a plasticizer for the cellulose nitrate, the amount of wax andoil together being at least equal to twice the amount of cellulosenitrate employed and the amount of oil being at least equal to theamount of wax employed, the non-volatile ingredients amounting to 1-20%by weight of the composition.

4. A water-re llent coatin composition for fabrics and t e likecomprising cellulose nitrate, a high melting parafiin wax, a nonvolatilenaphthene base oil, and a plasticizer for the cellulose nitrate, theamount of wax and oil together being at least equal to twice the amountof cellulose nitrate employed and the amount of oil being at least equalto the amount of wax employed, the non-volatile ingredients amounting to1-20% by weight of the composition.

5. A water-repellent coating composition for fabrics and the likecomprising cellulose nitrate having a viscosity of at least 4 seconds, abrittle, non-tacky, high melting paraflin wax, a non-volatile naphthenebase oil, and a lasticizer of the stcarate t pc for the celluosenitrate, the amount 0 wax and oil together being at least equal to twicethe amount of cellulose nitrate employed and the amount of oil being atleast equal to the amount of wax employed, the non-volatile ingredientsamounting to 1-20% by weight of the composition.

6. A water-repellent coating composition for fabrics and the likecomprising a cellulose derivative, a water-repellent wax, and anon-volatile oil, the amount of wax and oil together being equal to 2-15times the amount of cellulose derivative employed and the amount of oilbeing at least equal to the amount of wax employed, the non-volatileingredients amounting to 120% by weight of the composition.

7. A water-repellent coating composition for fabrics and the likecomprising cellulose nitrate, a water-repellent wax, and a nonvolatileoil, the amount of wax and oil together being equal to 2-15 times theamount of cellulose nitrate employed and the amount of oil being atleast equal to the amount of wax employed, the non-volatile ingmdientsamounting to 1-20% by weight of the composition.

8. A water-repellent coating composition for fabrics and the likecomprising cellulose nitrate, a high'melting parafiin wax, a nonvolatileoil, and a plasticizer for the cellulose nitrate, the amount of wax andoil together bein equal to 2-15 times the amount of cellu ose nitrateemployed and the amount of oil being at least equal to the amount of waxemployed, the non-volatile ingredients amounting to 1-20% by weight ofthe composition.

9. A water-re ellent coating composition for fabrics and the likecomprising cellulose nitrate, a high melting paraflin wax, a nonvolatilena hthene base oil, and a plasticizer for the celliilose nitrate, theamount of wax and oil together being equal to 2-15 times the amount ofcellulose nitrate employed and the amount of oil being at least equal tothe amount of wax employed, the non-volatile ingredients amounting to1-20% by weight of the composition.

10. A water-re llent coating composition 3 for fabrics and e like comrising cellulose nitrate having a viscosity 0 at least 4 seconds, abrittle, non-tacky, h' h melting paraflin wax, a non-volatile nap thenebase oil, and a plasticizer of the stearate type for the cellulosenitrate, the amount of wax and oil together being equal to 2-15 timesthe amount of cellulose nitrate employed and the amount of oil being atleast equal to the amount of wax employed, the non-volatile ingredientsamounting to 1-20% by weight of the composition.

In testimon whereof I afiix m signature.

G ORGE R. ENS NGER.

CERTIFICATE OF CORRECTION.

Patent No. 1,915,301. June 27, 1933.

GEORGE R. ENSMINGER.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 18, for "colloidal" read "colloided"; and line 61, for "a" read"as"; and that the said Letters Patent should be read with thesecorrections therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 22nd day of August, A. D, 1933.

M. J. Moore.

(Seal) Acting Commissioner of Patents.

the amount of wax employed, the non-volatile ingredients amounting to1-20% by weight of the composition.

10. A water-re llent coating composition 3 for fabrics and e like comrising cellulose nitrate having a viscosity 0 at least 4 seconds, abrittle, non-tacky, h' h melting paraflin wax, a non-volatile nap thenebase oil, and a plasticizer of the stearate type for the cellulosenitrate, the amount of wax and oil together being equal to 2-15 timesthe amount of cellulose nitrate employed and the amount of oil being atleast equal to the amount of wax employed, the non-volatile ingredientsamounting to 1-20% by weight of the composition.

In testimon whereof I afiix m signature.

G ORGE R. ENS NGER.

CERTIFICATE OF CORRECTION.

Patent No. 1,915,301. June 27, 1933.

GEORGE R. ENSMINGER.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 18, for "colloidal" read "colloided"; and line 61, for "a" read"as"; and that the said Letters Patent should be read with thesecorrections therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 22nd day of August, A. D, 1933.

M. J. Moore.

(Seal) Acting Commissioner of Patents.

